Instruments and Methods for Minimally Invasive Spine Surgery

ABSTRACT

A minimally invasive surgical method includes inserting a first port that defines a first pathway to a first vertebra, advancing a first anchor through the first port to the first vertebra, inserting a second port that defines a second pathway to a second vertebra, advancing a second anchor through the second port to the second vertebra, positioning a first end of a fixation element in the first port, and advancing the first end of the fixation element subcutaneously through an opening in the first port and an opening in second port to the second anchor. A surgical access port includes a proximal end, a distal end, and a sidewall defining a lumen extending from the proximal end to the distal end. The port may include a first opening formed in the sidewall that defines a passageway for medical hardware from the lumen to external to the port.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/914,983, filed Aug. 10, 2004, which is a continuation-in-part of U.S.patent application Ser. No. 10/021,809, filed Oct. 30, 2001, and is acontinuation-in-part of U.S. patent application Ser. No. 10/024,221,filed Oct. 30, 2001. Each of the aforementioned patent applications isincorporated herein by reference.

BACKGROUND

For a number of known reasons, spinal fixation devices are used inorthopedic surgery to align and/or fix a desired relationship betweenadjacent vertebral bodies. Such devices typically include a spinalfixation element, such as a relatively rigid fixation rod or plate, thatis coupled to adjacent vertebrae by attaching the element to variousanchoring devices, such as hooks, bolts, wires, or screws. The fixationelements can have a predetermined contour that has been designedaccording to the properties of the target implantation site, and onceinstalled, the fixation element holds the vertebrae in a desired spatialrelationship, either until desired healing or spinal fusion has takenplace, or for some longer period of time.

Spinal fixation elements can be anchored to specific portions of thevertebrae. A variety of anchoring devices have been developed tofacilitate engagement of a particular portion of the bone. Pedicle screwassemblies, for example, have a shape and size that is configured toengage pedicle bone. Such screws typically include a threaded shank thatis adapted to be threaded into a vertebra, and a head portion having arod-receiving element, often in the form of a U-shaped recess formed inthe head. A set-screw, plug, or similar type of closure mechanism isused to lock the fixation element, e.g., a spinal rod, into therod-receiving head of the pedicle screw. In use, the shank portion ofeach screw is threaded into a vertebra, and once properly positioned, arod is seated through the rod-receiving member of each screw and the rodis locked in place by tightening a cap or other closure mechanism tosecurely interconnect each screw and the fixation rod.

Recently, the trend in spinal surgery has been moving toward providingminimally invasive devices and methods for implanting bone anchors andspinal fixation devices. One such method, for example, is disclosed inU.S. Pat. No. 6,530,929 of Justis et al. and it utilizes twopercutaneous access devices for implanting an anchoring device, such asa spinal screw, into adjacent vertebrae. A spinal rod is then introducedthrough a third incision a distance apart from the percutaneous accesssites, and the rod is transversely moved into the rod-engaging portionof each spinal screw. The percutaneous access devices can then be usedto apply closure mechanisms to the rod-engaging heads to lock the rodtherein. While this procedure offers advantages over prior art invasivetechniques, the transverse introduction of the rod can cause significantdamage to surrounding tissue and muscle.

Accordingly, there remains a need for improved minimally invasivedevices and methods for treatment of spinal disorders.

SUMMARY

Disclosed herein are instruments and methods that facilitate thetreatment of spinal disorders in a minimally invasive manner. Inparticular, the disclosed methods permit the delivery and implanting ofone or more bone anchors and/or one or more fixation elements, forexample, a spinal rod, in a minimally invasive manner thereby limitingtrauma to surrounding tissue. Moreover, certain exemplary methodsdisclosed herein facilitate the removal of diseased disc material andthe placement of an interbody fusion device to promote spinal fusion, onone or both sides of the spine, in a minimally invasive manner. Also,disclosed herein are instruments that facilitate the subcutaneousdelivery and connection of a fixation element, such as a spinal rod, toa bone anchor.

In one exemplary embodiment, an exemplary minimally invasive surgicalmethod comprises making a first incision in a patient, positioning afirst port in the first incision, advancing a distal end of the portinto proximity to a vertebra, and positioning an instrument through anopening proximate the distal end of the port.

In one exemplary embodiment, an exemplary minimally invasive surgicalmethod comprises inserting a first port that defines a first pathway toa first vertebra, advancing a first anchor through the first port to thefirst vertebra, inserting a second port that defines a second pathway toa second vertebra, advancing a second anchor through the second port tothe second vertebra, positioning a first end of a fixation element inthe first port, and advancing the first end of the fixation elementsubcutaneously through an opening in the first port and an opening insecond port to the second anchor.

In one exemplary embodiment, an exemplary minimally invasive surgicalmethod comprises making a first incision in a patient, positioning afirst port in the first incision, advancing a first anchor through afirst pathway defined by the first port to a first anchor site on thefirst vertebra, making a second incision in the patient, positioning asecond port in the second incision, advancing a second anchor through asecond pathway defined by the second port to a second anchor site on thesecond vertebra, positioning a first end of a fixation element in thefirst port, advancing the first end of the fixation elementsubcutaneously through an opening in the first port and an opening insecond port to the second anchor, and coupling the fixation element tothe first anchor and the second anchor.

In one exemplary embodiment, an exemplary surgical access port comprisesa proximal end, a distal end spaced apart a distance from the proximalend and a sidewall defining a lumen extending from the proximal end tothe distal end. In the exemplary port, the lumen has a length sufficientto at least span from a skin incision to proximate a vertebra. Theexemplary port may include a first opening formed in the sidewall thatdefines a passageway for medical hardware from the lumen to external tothe port.

In one exemplary embodiment, a system for minimally invasive spinesurgery comprises a first dilator having a first diameter and a surgicalaccess port. In the exemplary system, the port may comprise a proximalend, a distal end spaced apart a distance from the proximal end, and asidewall defining a lumen extending from the proximal end to the distalend. In the exemplary system, the lumen of the port may have a lengthsufficient to at least span from a skin incision to proximate a vertebraand may have a diameter greater than the first diameter. The exemplaryport may have a first opening formed in the sidewall that defines apassageway for medical hardware from the lumen to external to the port.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the methods and instrumentsdisclosed herein will be more fully understood by reference to thefollowing detailed description in conjunction with the attached drawingsin which like reference numerals refer to like elements through thedifferent views. The drawings illustrate principles of the methods andinstruments disclosed herein and, although not to scale, show relativedimensions.

FIG. 1 is a perspective view of an exemplary embodiment of a surgicalaccess port, illustrating an opening formed in a sidewall of the port;

FIG. 2 is a side view of the surgical access port of FIG. 1;

FIG. 3 is a bottom view of the surgical access port of FIG. 1;

FIG. 4 is a front view of an exemplary embodiment of a surgical accessport, illustrating a first opening formed in a sidewall of the port;

FIG. 5 is a rear view of the surgical access port of FIG. 4,illustrating a second opening formed in the sidewall of the port;

FIG. 6 is a bottom view of the surgical access port of FIG. 4;

FIG. 7 is a side view in cross section of a first surgical access portand a second surgical access, illustrating an instrument systemcomprising a first instrument and a second instrument positioned in theports to facilitate creation of a subcutaneous pathway between theports;

FIG. 8 is a front view of the second instrument of the instrument systemillustrated in FIG. 7;

FIG. 9 is a side view in cross section of the ports of FIG. 7,illustrating the creation of a subcutaneous pathway between the ports;

FIG. 10 is a side view in cross section of the ports of FIG. 7,illustrating the placement of a spinal rod along the subcutaneouspathway between the ports and between bone anchors positioned in theports;

FIG. 11 is a side view in cross section of the ports of FIG. 7,illustrating the spinal rod in position between the ports;

FIG. 12 is a front view of an exemplary embodiment of a surgical accessport having an opening positioned between the distal end and theproximal end of the port; and

FIG. 13 is a side view of an exemplary embodiment of a surgical accessport having a proximal opening and a distal opening.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the instruments and methods disclosed herein.One or more examples of these embodiments are illustrated in theaccompanying drawings. Those of ordinary skill in the art willunderstand that the instruments and methods specifically describedherein and illustrated in the accompanying drawings are non-limitingexemplary embodiments and that the scope of the present invention isdefined solely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e. to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

The terms “comprise,” “include,” and “have,” and the derivativesthereof, are used herein interchangeably as comprehensive, open-endedterms. For example, use of “comprising,” “including,” or “having” meansthat whatever element is comprised, had, or included, is not the onlyelement encompassed by the subject of the clause that contains the verb.

FIGS. 1-3 illustrate an exemplary embodiment of a surgical access port10 for providing posterior, lateral, or anterior access to the spine.The exemplary port includes a proximal end 12, a distal end 14 spacedapart a distance from the proximal end 12 and a sidewall 16 defining alumen 18 extending from the proximal end 12 to the distal end 14. In theexemplary embodiment, the lumen 18 has a length sufficient to at leastspan from a skin incision to proximate a vertebra. The exemplary port10, in the illustrated embodiment, may include a first opening 30 formedin the sidewall 16 that defines a passageway for medical hardware, suchas, for example, surgical instruments and/or implants, from the lumen toexternal to the port, as discussed in more detail below. The lumen 18 ofthe exemplary port 10 provides unobstructed access from the proximal endof the lumen 18 to the distal end of the lumen 18 to permit theadvancement of instruments and/or implants through the lumen 18.

The size and shape of the exemplary port 10 may vary depending on theintended use of the port 10, for example, the region of the spine, e.g.,cervical, thoracic, or lumbar, the approach, e.g., posterior, lateral,or anterior, and the type(s) of implants and instruments desired to bepositioned through the lumen 18 of the port 10. In illustrated exemplaryembodiments, for example, the port 10 may have a length 1 sufficient tospan from a posterior skin incision to proximate a vertebra. The length1 of the port 10 may be varied, for example, depending on whether theport 10 is designed for use in the cervical, thoracic, or lumbar spine.For example, the port 10 may have a length 1 that allows the proximalend 12 of the port 10 to be positioned outside the patient's body, e.g.,proximal to or parallel to the level of the skin, while the distal end14 of the port 10 is in proximity to or abuts against a posteriorsurface of a vertebra.

Continuing to refer to FIGS. 1-3, the exemplary port 10 may have across-sectional shape and size that varies depending on the intended useof the port 10, for example, the region of the spine, e.g., cervical,thoracic, or lumbar, and the type(s) of implants and instruments desiredto be positioned through the lumen 18 of the port 10. In the exemplaryembodiment illustrated in FIGS. 1-3, for example, the exemplary port 10has a circular cross section. In other exemplary embodiments, such asthe exemplary port 110 illustrated in FIGS. 4-6, the port 110 may havean elliptical or oval cross-section. One skilled in the art willappreciate that the port 10 may have a cross section that is circular,rectangular, square, elliptical, polygonal or any other shape suitablefor providing surgical access to the spine. In the exemplary embodimentsillustrated in FIGS. 1-3 and 4-6, the port 10 and the port 100 each havea generally constant cross section, e.g., the size and/or shape of thecross section of the port does not vary along the length 1 of thecannula. In certain other exemplary embodiments, the cross section ofthe port may vary in size and shape along the length 1 of the cannula.For example, the width or diameter of the port may vary along the lengthof the cannula. In the exemplary embodiments illustrated in FIGS. 1-3and 4-6 the port 10 and the port 100 each have a continuous crosssection in the manner of, for example, a cannula. In certain otherembodiments, the port may have a non-continuous cross-section. Forexample, the port may have a C-shaped cross section or may include oneor more longitudinally oriented slots that interrupt the cross sectionalong the length 1 of the port. In certain exemplary embodiments, thedistal end 14 of the port 10 may be sized and shaped to facilitateengagement with the anatomy of the vertebra. For example, the distal end14 may have a beveled, tapered, and/or angled shape.

In the exemplary embodiment illustrated in FIGS. 1-3, the lumen 18 ofthe exemplary port 10 may have a diameter d that is sufficient to allowa spinal implant and/or instrument to be introduced therethrough.Examples of spinal implants that may be introduced through the port 10include spinal fixation elements, such as a plate, rod, or tether,interbody fusion devices, nucleus replacement devices, artificial discs,and fasteners, such as bone anchors. The diameter d of the lumen 18 maybe sized to allow any of these implants and associated instruments to beintroduced therethrough. In certain exemplary embodiments, the diameterd of the exemplary port 10 may be sized to provide access to a portionof a first vertebra, for example, the pedicle, e.g., for placement of abone anchor. In certain exemplary embodiments, the diameter d of theexemplary port 10 may be sized to span between a first vertebra and asecond vertebra to provide access to the first vertebra, the secondvertebra and the disk therebetween.

The exemplary port 10 may be constructed from any material suitable foruse in vivo, including metals, such as stainless steel or titanium,polymers, ceramics, or composite materials.

In certain exemplary embodiments, the port 10 may be constructed from atranslucent polymer. The outer surface of the sidewall 16 of theexemplary port 10 may be contoured to minimize sharp edges and, thereby,inhibit injury to muscles and tissues surrounding the port 10. Inaddition, the outer surface of the sidewall 16 of the port 10 mayinclude surface texturing to facilitate holding retracted tissue inplace, in particular, away from the distal end of the lumen 18. Thesurface texturing may be, for example, one or more annular grooves 20formed in the outer surface of the sidewall 16 of the port 10. Incertain embodiments, the surface texturing may be surface roughening,ridges, spiral grooves, and/or materials with a high coefficient offriction. In certain exemplary embodiments, the outer surface of thesidewall 16 of the port 10 is coated with silicon to facilitate holdingrefracted tissue.

The proximal end 12 of the exemplary port 10 may optionally include apositioning ring 24 that facilitates the positioning of the port 10. Thepositioning ring 24 may be generally annular in shape and may have anouter diameter that is greater that the diameter of the port 10. Thepositioning ring 24, in the exemplary port 10, may have a taperedopening 26 that tapers to the diameter of the lumen 16 of the port tofacilitate positioning of implants and instruments into the port 10. Thepositioning ring 24 may include one or more tabs 28 that facilitateconnection of the positioning ring 24 and, thus, the port 10, to aclamp, such as a C-arm.

The exemplary port 10 may be configured to hold a light source thatilluminates the lumen 18 and/or the distal end 32 of the port 10, forexample, during a procedure performed in the port 10. In one exemplaryembodiment, the proximal end 12 may include a coupling mechanism, forexample, a clamp, for hold one or more light sources, for example, afiber optic cable or a light tube, that is oriented to illuminate thelumen and the distal end of the port 10. In other exemplary embodiments,one ore more light sources, for example, a fiber optic cable or a lighttube, may be embedded within the sidewalls 16 of the port 10 toilluminate the lumen 18 and/or the distal end 14 of the port 10.

Continuing to refer to FIGS. 1-3, the exemplary port 10 may include oneor more openings 30 formed in the sidewall 16 of the port 10. In theillustrated embodiment, for example, the port 10 includes a singleopening 30 formed in the sidewall 16 of the port 10. The opening 30defines a passageway for medical hardware, for example spinalinstruments and implants, between the lumen 18 and the exterior of theport 10. For example, once the port 10 is positioned in proximity to asurgical site, medical hardware may be advanced subcutaneously from thelumen 18 to external to the port 10, as indicated by arrow A in FIG. 3.Alternatively, medical hardware may be advanced subcutaneously fromexterior to the port 10 into the lumen 18 through the passageway, asindicated by arrow A′ in FIG. 3.

The size, shape, position, and number of the opening(s) 30 may be varieddepending on, for example, the procedure selected and the medicalhardware employed. The exemplary ports 10, 110, and 210, illustrated inFIGS. 1-3, 4-6, and 12, respectively, provide examples of ports havingvarious sized, shaped, and positioned opening(s). For example, in theexemplary embodiment illustrated in FIGS. 1-3, the opening 30 may besized, shaped, and positioned to facilitate delivery of a spinalfixation element, such as a plate, rod, cable, or tether, to a siteexterior to the port 10. The opening 30, in the exemplary port 10, is anelongated slot extending proximally from the distal end 14 of the port10. The opening 30 is oriented generally parallel to the longitudinalaxis 22 of the port 10 and defines a passageway that is orientedapproximately parallel to the longitudinal axis 22 of the port, asindicated by arrow A in FIG. 3. The opening 30, in the exemplaryembodiment, has length l.sub.s and a width w.sub.s that are selected toallow at least a portion of a fixation element, such as a spinal rod, tobe manipulated from within the lumen 18 through the passageway definedby the opening 30. The opening 30 is positioned at the distal end 14 ofthe port 10 and has an open, i.e., unobstructed, distal end 32.

FIGS. 4-6 illustrate an exemplary embodiment of a surgical access port110 having two openings 130A, 130B formed in a sidewall 116 of the port110 to facilitate passage of medical hardware between the lumen 118 ofthe port 110 and the exterior of the port 110. The size, shape,position, and number of the openings 130A,B may be varied depending on,for example, the procedure selected and the medical hardware employed.For example, the openings 130A,B may be sized, shaped, and positioned tofacilitate delivery of a spinal fixation element, such as a plate, rod,cable, or tether, to a site exterior to the port 110 or to receive aspinal fixation element delivered to the lumen 118 of the port 110. Theopenings 130A,B in the exemplary port 110, are elongated slots extendingproximally from the distal end 114 of the port 110. The openings 130A,B,in the illustrated embodiment, are oriented generally parallel to thelongitudinal axis 122 of the port 110. The openings 130A, 130B arepositioned generally opposite from each other, as illustrated in FIG. 6,and each opening 130A,B defines a passageway oriented approximatelyperpendicular to the longitudinal axis 122 of the port 110 for thepassage of medical hardware, such as instruments or implants, out of thelumen 118 of the port 110, as indicated by arrows B, and/or into thelumen 118 of the port, as indicated by arrows B′. In the illustratedembodiment, for example, the length l.sub.sa of the first opening 130Ais less than the length lsb of second opening 130B. In other exemplaryembodiments, the length l.sub.sa of the first opening 130A may be equalto the length lsb of second opening 130B.

FIG. 12 illustrates another exemplary embodiment of a surgical accessport 210 having an opening 230 formed in a sidewall of the port 210. Theopening 230 in the exemplary port 210 is an elongated slot that isoriented approximately parallel to the longitudinal axis 222 of the port120 and is positioned between the distal end 214 and the proximal end212 of the port 210. Unlike the exemplary ports 10, 110, describedabove, the opening 212 is not open at the distal end thereof. Theposition of the opening 230, as well as the size, shape, and number ofopening(s) may be varied depending on, for example, the procedureselected and the medical hardware employed. For example, the opening 230in the illustrated embodiment is positioned proximate the distal end 214of the port 210. In other exemplary embodiments, the opening 230 may bepositioned proximate the proximal end of the port 210.

FIG. 13 illustrates an exemplary embodiment of a surgical access port910 having a plurality of openings 930A, 930B formed in the sidewall 916of the port 910. In the illustrated exemplary embodiment, the port 910includes a distal opening 930A extending proximally from the distal end914 of the port 910 and a proximal opening 930B extending distally fromthe proximal end 912 of the port 910. In the illustrated exemplaryembodiment, the distal opening 930A and the proximal opening 903B areopposed from one another and overlap along at least a portion of thelongitudinal axis 922 of the port 910.

One skilled in the art will appreciate that the size, shape, position,orientation, and number of opening(s) is not limited to the embodimentsdescribed above. For example, the opening(s) may be circular, square,oval, or polygonal in shape and any number of openings may be employed.

In certain exemplary embodiments, the port may include indicia forindicating the location of the opening(s) on the port. For example, theproximal end 12 of the exemplary port 10 illustrated in FIGS. 1-3 mayinclude one or more raised ridges 32 that indicate the position andorientation of the opening 30 in the sidewall 16 of the port 10. In theillustrated embodiment, a first ridge 32A is circumferentially alignedwith the opening 30 and the second ridge 32B is diametrically opposed tothe opening 30. In alternative embodiments, indicia for indicating theposition of the opening in the sidewall of the slot may be a groove ormark on the proximal end and/or the sidewall or within the lumen of theport.

The surgical access ports disclosed herein may be employed to providesurgical access to the spinal anatomy. In one exemplary embodiment, asurgical access port, such as any of the exemplary ports describedabove, may be inserted, for example through an incision, into proximityto a first vertebra of the spine. For example, the distal end 14 of thesurgical access port 10 illustrated in FIGS. 1-3 may be advanced intoproximity to the first vertebra to define a first pathway to the firstvertebra through the lumen 18 of the surgical access port 10. Aninstrument and/or implant may be advanced through the lumen 18 of theport 10 into proximity to the first vertebra to perform a procedure atthe first vertebra or to perform a procedure at a location proximal tothe first vertebra. Such procedures may be performed by manipulating aninstrument and/or implant within the lumen 18 of the port 10 and/or bymanipulating the instrument and/or implant through an opening 30 in thesidewall of the port 10. For example, an instrument and/or an implantmay be advanced through the opening 30 to perform a procedure at thefirst vertebra or a position proximate the first vertebra, such as at asecond vertebra that is adjacent to the first vertebra. Exemplaryprocedures include laminotomy, facetectomy, foraminotomy, nerve rootretraction, discectomy, and/or positioning of a spinal implant such as aspinal fixation element, such as a plate, rod, or tether, an interbodyfusion device, a nucleus replacement device, an artificial disc, and afastener, such as a bone anchor.

In certain exemplary embodiments, the distal end of a surgical accessport, such as any of the exemplary ports described above, may be movedbetween two or more locations to perform procedures at multiple sites.For example, the distal end 14 of the exemplary port 10 may be advanced,e.g., through an incision, into proximity to a first and secondvertebrae. The proximal end 12 of the port 10 may be manipulated to movethe distal end 14 into alignment with at least a portion of the firstvertebra by, for example, angling the proximal end 12 relative to theskin incision in a procedure generally referred to as “wanding.” Aprocedure may be performed at the first vertebra, such as, for example,placement of a first bone anchor in the first vertebra. The proximal end12 of the port 10 may be manipulated to move the distal end 14 intoalignment with at least a portion of the second vertebra and a proceduremay be performed at the second procedure, such as, for example,placement of a second bone anchor in the second vertebra. A fixationelement, such as a spinal rod, may be coupled to the first and secondbone anchors using the surgical access port. For example, a first end ofthe fixation element may be positioned in the port and advanced throughthe lumen 16 to the opening 30. The first end of the fixation elementmay be advanced subcutaneously through the opening 30 toward the firstvertebra. The fixation element may be coupled to the second anchor by,for example, delivering a closure mechanism, such as a set screw or cap,through the port 10 to the second anchor. The proximal end 12 of theport 10 may be manipulated to the move the distal end 14 into alignmentwith the first vertebra. During movement of the distal end 14 of theport 10 to the first vertebra, the opening may be aligned with thefixation element such that the distal end 14 moves along the fixationelement toward the first vertebra. Once the distal end 14 of the port 10is aligned with the first end of the fixation element may be positionedrelative to the first anchor and the fixation element may be coupled tothe first anchor.

The fixation element may be advanced within the lumen of the port andsubcutaneously through the opening(s) in the port using any conventionalinstrument for manipulating a spinal fixation element. In certainexemplary embodiments, the fixation element may be advanced through thelumen of the port in orientation substantially parallel to thelongitudinal axis of the port. The fixation element may be manipulatedthrough the opening(s) in the port to an orientation that is angled withrespect to the longitudinal axis of the port. In certain embodiments,the fixation element may be oriented substantially perpendicular to thelongitudinal axis of the port. Exemplary instruments for manipulating aspinal fixation element between two or more orientations are disclosedin U.S. patent application Ser. No. 10/737,166, filed Dec. 16, 2004;U.S. patent application Ser. No. 10/737,538, filed Dec. 16, 2004; andU.S. patent application Ser. No. 60/542,548, filed Apr. 27, 2004, eachof the aforementioned patent applications are incorporated herein byreference.

In certain exemplary embodiments, two or more surgical access ports,such as any of the exemplary ports described above, may be employed toprovide access to multiple sites proximate the spine. For example, twosurgical access ports may be employed to facilitate subcutaneousplacement of a spinal fixation element between to or more vertebrae. Inone exemplary embodiment, for example, a first port, such as exemplaryport 10, may be inserted to define a first pathway to a first vertebra.A first bone anchor may be advanced through the lumen 16 of the firstport 10 to the first vertebra. A second port, such as exemplary port 10,may be inserted to define a second pathway to a second vertebra, which,for example, may be adjacent the first vertebra. A second bone anchormay be advanced through the lumen of the second port to the secondvertebra. A spinal fixation element, for example, a spinal rod, may bepositioned in the lumen of the first port. An end of the spinal fixationelement may advanced through an opening 30 of the first port 10 andadvanced subcutaneously to an opening 30 in the second port. The spinalfixation element may be coupled to the first anchor by delivering aclosure mechanism through the lumen 16 of the first port and to thesecond anchor by delivering a closure mechanism to the second anchorthrough the second port.

FIGS. 7-11 schematically illustrate an exemplary method of minimallyinvasive surgery that provides for the placement of multiple boneanchors and a fixation element on one or both sides of a patient'sspine. The exemplary method may be employed to stabilize and align twoor more bone segments, in particular, two vertebrae (VB.sub.1,VB.sub.2), in a minimally invasive manner that reduces trauma toadjacent tissue.

Referring to FIG. 7, the exemplary method may comprise making a firstincision in a patient and positioning a first surgical access port 310,such as an exemplary surgical access port described above, in the firstincision. In the illustrated embodiment, the first port 310 is analogousin construction to the exemplary surgical access port illustrated inFIGS. 4-6 and described above. The distal end 314 of the port 310 isadvanced into proximity to a first vertebra VB.sub.1 and the lumen 316of the first port 310 defines a first pathway from the incision to thefirst vertebra VB.sub. 1.

The first incision may be a minimally invasive incision made in thepatient's skin that is expanded, for example, by retraction and ordilation, to create a pathway from the first incision to the proximatethe first vertebra VB.sub. 1. The first incision 14 may be expanded tocreate the pathway in any conventional manner. In certain embodiments,for example, the first incision may be expanded by dilation to thedesired size, shape, and orientation. For example, the first incisionmay be sequentially dilated using a plurality of dilators to create thepathway to the first vertebra. Exemplary methods and instruments forserial dilation are described in commonly owned U.S. Pat. No. 6,159,179,entitled Cannula and Sizing and Insertion Method; U.S. patentapplication Ser. No. 10/024,221, filed Oct. 30, 2001, entitledNon-Cannulated Dilators; and U.S. patent application Ser. No.10/021,809, filed Oct. 30, 2001, entitled Configured and Sized Cannulas,each of which is incorporated herein by reference. In other embodiments,a single dilator may be employed to expand the incision. Once dilationis concluded, the first port 310 may be positioned into the dilatedfirst incision to define a first passageway to the vertebra.Alternatively, a retractor may be inserted into the dilated firstincision to further expand the first incision and then the first portmay be positioned in the first incision.

In certain exemplary embodiments, the first incision may be expanded byinserting one or more retractors into the incision and expanding theincision to the desired size, shape, and orientation by expanding theretractor accordingly. Any type of conventional retractor or retractorsmay be employed to expand the first incision. For example, suitableretractors are described in commonly owned U.S. patent application Ser.No. 10/815,182, filed Mar. 31, 2004, entitled Telescoping BladeAssemblies and Instruments for Adjusting an Adjustable Blade; U.S.Provisional Patent Application Ser. No. 60/530,655, filed Dec. 18, 2003,entitled Surgical Retractor Systems, Illuminated Cannula and Methods ofUse; and U.S. patent application Ser. No. 10/808,687, entitled SurgicalRetractor Positioning Device, each of which are incorporated herein byreference.

In certain exemplary embodiments, the first incision may be expanded tocreate a pathway by an intermuscular procedure that includes locating amuscle plane separating two muscles and separating the muscles at themuscle plane to create the first pathway. For example, in certainexemplary methods, the intermuscular plane separating the multifidus andlongissimus muscles may be located through the first incision. Themultifidus and longissimus muscles may be separated at the muscle planeby blunt dissection, for example, by inserting a finger or aninstrument, such as a retractor, through the muscle plane and advancingthe finger or instrument to the vertebra to create the pathway to thevertebra. Intermuscular procedures are described in detailed in U.S.Pat. No. 6,692,434, entitled Method and Device for Refractor forMicrosurgical Intermuscular Lumbar Arthrodesis; U.S. patent applicationSer. No. 10/060,905, filed Jan. 29, 2002, entitled Retractor and Methodfor Spinal Pedicle Screw Placement; and New Uses and Refinements of theParaspinal Approach to the Lumbar Spine, L. L. Wiltse and C. W. Spencer,Spine, Vol. 13, No. 6, Nov. 6, 1988, each of which is incorporatedherein by reference.

The first incision may be a percutaneous skin incision that has a shapeand extent that is less than, equal to, or slightly greater than, theextent of the instruments and implants being inserted thereto. Incertain exemplary embodiments, for example, the incision may be a stabincision that is expanded to facilitate positioning of the first port310 therethrough.

Continuing to refer to FIG. 7, a first anchor 300 may be advancedthrough the first pathway defined by the lumen 316 of the first port 310to an anchor site on the first vertebra VB.sub.1. The first bone anchor300 may be any type of conventional bone anchor, including, for example,a monoaxial or polyaxial bone screw, a bolt, or a hook. The first boneanchor 300 may be implanted into any portion of the first vertebraVB.sub.1 respectively, in any conventional manner through the firstincision. In the illustrated embodiment, the first bone anchor 300 isimplanted into a first pedicle P.sub.1 of the first vertebra VB.sub.1.

A second surgical access port 410 may be inserted through a secondincision to define a second pathway from the second incision to a secondvertebra VB.sub.2. In the illustrated embodiment, the second port 410 isanalogous in construction to the first port except the second port 410has a single opening 430 and the first port 310 has two openings 430A,430B. The opening 430 in the second port may be aligned with at leastone of the openings 330A, 330B in the first port 310 by, for example,rotating one or both of the ports. Alignment indicia on the proximal endof the ports may be employed to facilitate alignment of the openings. Inthe illustrated embodiment, the opening 430 in the second port 410 isaligned with the opening 330A of the first port 310.

The second incision may be expanded to create a pathway to the secondvertebra VB.sub.2 in a manner analogous to the first incision describedabove. The second incision may be a percutaneous skin incision in amanner analogous to the first incision.

Continuing to refer to FIG. 7, a second bone anchor 302, e.g., apolyaxial bone screw analogous to the first bone anchor, may be advancedthrough the second pathway defined by the lumen 416 of the second port410 to a second anchor site on the second vertebra VB.sub.2. The secondbone anchor 302 may be implanted into any portion of the second vertebraVB.sub.2 respectively, in any conventional manner through the secondincision. In the illustrated embodiment, the second bone anchor 302 isimplanted into a second pedicle P.sub.2 of the second vertebra VB.sub.2.

A spinal fixation element, for example, a spinal rod, may be positionedin the first port 310 and advanced subcutaneously through the opening330A and the opening 430 to the second anchor 302. In the exemplarymethod, a first instrument 500 may be employed for creating asubcutaneous pathway between the first port 310 and the second port 410to facilitate advancement of the spinal fixation element to the secondanchor 302. The exemplary first instrument 500, as illustrated in FIG.7, includes a proximal handle 502, a shaft 504 having a longitudinalaxis 506, and a distal tip 508 that is oriented at an angle to the shaft504 and is configured to dissect tissue. The shaft 504 of the exemplaryinstrument is preferably sized to fit through the lumen of the firstport 310. The distal tip 508 may be oriented at an angle greater than orequal to approximately 45.degree. to the longitudinal axis 506 of theshaft 500, and, in the illustrated embodiment, is oriented approximatelyperpendicular to the longitudinal axis 506 of the shaft 500, althoughone skilled in the art will appreciate that other angles suitable forcreating a subcutaneous pathway may be utilized. The distal tip 508, inthe illustrated embodiment, terminates at a tip 510 suitable fordissecting tissue. The length of the distal tip 508, indicated by arrow512 in FIG. 7, may be varied depending on the procedure and the anatomy.In the illustrated embodiment, for example, the length of the distal tipis selected to span the distance between the distal end 314 of the firstport 310 and the distal end of the second port 410. In certain exemplaryembodiments, the tip 510 of the instrument 500 may be sized to interfacewith a bone anchor positioned in the first port 310 and/or the secondport 410. For example, the tip 510 of the instrument 500 may be sized toseat within the spinal fixation element receiving portion of the boneanchor. In the case of a polyaxial bone screw, for example, the tip 510of the instrument 500 may be sized to seat within the spinal rodreceiving slot of the polyaxial bone screw.

Continuing to refer to FIG. 7, the first instrument 500 may bemanipulated to advance the distal tip 508 through the opening 330A inthe first port 310 to create a subcutaneous pathway between the opening330A in the first port 310 and the opening 430 in the second port 410.

In certain alternative embodiments, the spinal fixation element may havea tip configured to create a subcutaneous pathway. For example, thefixation element may be a spinal rod having a tip suitable for tissuedissection. Advancement of the spinal rod to the second anchor maycreate the subcutaneous pathway between the first port 310 and thesecond port 410.

In certain exemplary embodiments, including the illustrated embodiment,a second instrument 600 may be used in cooperation with the firstinstrument 500 to facilitate the creation of a subcutaneous pathwaybetween the distal end 314 of the first port 310 and the distal end 414of the second port 410. The exemplary second instrument 600, asillustrated in FIGS. 7-10, includes a proximal handle 602, a shaft 604having a longitudinal axis 606, and a distal tip 608 oriented at anangle to the longitudinal axis 606 of the shaft 604. The shaft 604 ofthe exemplary second instrument 600 is preferably sized to fit throughthe lumen 416 of the second port 610. The distal tip 608 of the secondinstrument 600, in the illustrated embodiment, is oriented approximatelyperpendicular to the longitudinal axis 606 of the shaft 600, althoughone skilled in the art will appreciate that other angles suitable forcreating a subcutaneous pathway may be utilized. The distal tip 608 maybe sized to receive at least a portion of the distal tip 508 of thefirst instrument 500. For example, in the exemplary embodiment, thedistal tip 608 of the second instrument 600 may be generally arcuate incross-section and may include a proximal surface 610 for receiving thedistal tip 508 of the first instrument 500. The proximal surface 610 maybe complementary in size and shape to the distal tip 508 of the firstinstrument 500 to facilitate alignment of the distal tip 508 of thefirst instrument 500 and the distal tip 608 of the second instrument600. For example, the proximal surface 610 may have a curvatureanalogous to the curvature of the distal tip 508 of the first instrument500. In certain exemplary embodiments, the distal tip 508 of the firstinstrument 500 and the distal tip 608 of the second instrument 600 maybe coaxially aligned when engaged with one another. One skilled in theart will appreciate the distal tip 608 of the second instrument 600 mayhave other configurations suitable for receiving the distal tip 508 ofthe first instrument 500. For example, the distal tip 608 of the secondinstrument 600 may be generally cylindrical in shape, having forexample, a generally circular cross section, for receiving the distaltip 508 of the first instrument 500 in a telescoping relationship. Incertain exemplary embodiments, the tip 610 of the instrument 600 may besized to interface with a bone anchor positioned in the first port 310and/or the second port 410. For example, the tip 610 of the instrument600 may be sized to seat within the spinal fixation element receivingportion of the bone anchor. In the case of a polyaxial bone screw, forexample, the tip 610 of the instrument 600 may be sized to seat withinthe spinal rod receiving slot of the polyaxial bone screw.

One skilled in the art will appreciate that use of the first instrument500 and/or the second instrument 600 is optional. The first instrument500 may be employed independent of the second instrument 600 to create asubcutaneous pathway between the distal end 314 of the first port 310and the distal end 414 of the second port 410. As discussed above, incertain exemplary embodiments, the subcutaneous pathway may be createdwithout instruments by, for example, advancement of the spinal fixationelement from the first port to the second port.

In the exemplary method, the distal tip 508 of the first instrument 500is advanced to the opening 430 in the second port 410 and into thedistal tip 608 of the second instrument 600, thereby creating thesubcutaneous pathway. As illustrated in FIG. 9, the first instrument 500and the second instrument 600 may be cooperatively manipulated tofacilitate creation and expansion of the subcutaneous pathway betweenthe distal end 314 of the first port 310 and the distal end 414 of thesecond port 410. For example, the proximal handle 502 of the firstinstrument 500 and the proximal handle 602 of the second instrument 600may be moved in unison to cause the distal tips 508, 608 to move inunison between the distal ends of the first and second ports 310, 410.

Referring to FIG. 10, a spinal fixation element, for example a spinalrod 700, may be advanced subcutaneously to the second anchor 302 usingan instrument for manipulating a spinal fixation element, as describedabove. In the illustrated embodiment, an exemplary spinal rodmanipulating instrument 800 includes a proximal handle 802, a shaft 804,and a distal end 806 that may be pivotally connected at a pivot point810 to a first end 702 of the exemplary spinal rod 700. The exemplaryrod manipulating instrument 800 allows the rod 700 to be positioned inthe first port 310 in an orientation approximately parallel to thelongitudinal axis of the first port 310 and to be pivoted to anon-parallel orientation to facilitate advancement of the rod 700through a distal opening 330 in the port 310. In the exemplaryembodiment, the rod 70 may be pivoted to an orientation that issubstantially perpendicular to the longitudinal axis of the first port310 to allow the second end 704 of the rod 700 to be advanced throughthe opening 330A and subcutaneously to the second port 410, asillustrated in FIG. 10. In the exemplary embodiment, the port 310 isprovided with two opposed openings 330 A,B to facilitate transition ofthe rod 700 to an orientation suitable for subcutaneous advancement ofthe rod. For example, the opening 330A allows the first end 702 of therod 700 to be pivoted to a non-parallel orientation, as illustrated byarrow P in FIG. 10. The manipulating instrument 800 may be employed tofacilitate subcutaneous advancement of the rod 700 to the second port410.

In certain exemplary embodiments, the second instrument 600 also may beemployed to facilitate subcutaneous advancement of the rod 700 to thesecond port 410, as illustrated in FIG. 10. The distal tip 608 of thesecond instrument 600 may receive a portion of the rod 700, for example,the second end 704 of the rod 700, and may guide the rod 700 along thesubcutaneous pathway to the second port 410. One skilled in the art willappreciate that use of the second instrument 600 is optional and that incertain exemplary embodiments the rod 700, or other fixation element,may be advanced to the second port 410 independent of an instrumentpositioned in the second port 410.

Once the spinal fixation element, e.g., rod 700, is advanced to thesecond port 410, the fixation element may be coupled to the first anchor300 and the second anchor 302. For example, a closure mechanism 304B maybe advanced through the first port 310 to the first anchor 300 and aclosure mechanism 304B may be advanced through the second port 410 tothe second anchor 302, as illustrated in FIG. 11. The closure mechanismsmay be coupled to the bone anchors to secure the spinal fixation elementto the bone anchors.

In certain exemplary embodiments, the disk space D between the first andsecond vertebrae VB.sub.1, VB.sub.2 may be accessed though the firstport 310 and/or the second port 410. For example, the distal end 314 ofthe first port 310 and/or the distal 414 end of the second port 410 maybe moved into alignment with the disk space. In certain exemplaryembodiments, the first port 310 and the second port 410 may be selectedto have a size sufficient to provide access to a vertebra and theadjacent disk space. Accessing the disk space allows one or moreprocedures to be performed at the disk space. For example, all or aportion of the disk material may be removed from the disk space D. Incertain embodiments, an interbody fusion device, including, for example,bone graft or a cage, may be placed in the disk space D to promotefusion of the first and second vertebrae VB.sub.1, VB.sub.2. In certainembodiments, an artificial disk may be placed in the disk space D.

In certain exemplary embodiments, the disk space D between the first andsecond vertebrae VB.sub.1, VB.sub.2 may be accessed through a separateincision, e.g., a third, incision, rather than the first incisionthrough which the first port 310 is positioned and the second incisionthrough which the second port 410 is positioned.

One skilled in the art will appreciate that the order of the steps ofthe exemplary method described in connection with FIGS. 7-11 is merelyexemplary and the steps may be carried out in one or more differentorders. For example, in certain exemplary embodiments, the subcutaneouspathway between the first port and the second port may be created beforeadvancing the first anchor through the first port and before advancingthe second anchor through the second port. In other exemplaryembodiments, the subcutaneous pathway may be created after advancing thefirst anchor through the first port and before advancing the secondanchor through the second port. In other exemplary embodiments, thefirst port and the second port may be placed before advancement of thefirst anchor and the second anchor through the ports.

While methods and instruments of the present invention have beenparticularly shown and described with reference to the exemplaryembodiments thereof, those of ordinary skill in the art will understandthat various changes may be made in the form and details herein withoutdeparting from the spirit and scope of the present invention. Those ofordinary skill in the art will recognize or be able to ascertain manyequivalents to the exemplary embodiments described specifically hereinby using no more than routine experimentation. Such equivalents areintended to be encompassed by the scope of the present invention and theappended claims.

1-40. (canceled)
 41. A surgical access port comprising: a proximal end;a distal end spaced apart a distance from the proximal end; and asidewall defining a lumen extending from the proximal end to the distalend, the lumen having a length sufficient to at least span from a skinincision to proximate a vertebra, and a first opening formed in thesidewall, the first opening defining a passageway for medical hardwarefrom the lumen to external to the port.
 42. The port of claim 41,wherein the passageway is oriented generally perpendicular to the lumen.43. The port of claim 41, wherein the first opening is sized to pass aspinal implant therethrough.
 44. The port of claim 43, wherein thespinal implant is a spinal rod.
 45. The port of claim 43, wherein thespinal implant is one or more components of a spinal anchor.
 46. Theport of claim 41, wherein the first opening extends proximally from thedistal end.
 47. The port of claim 41, wherein the first opening isinterposed between the distal end and the proximal end.
 48. The port ofclaim 39, further comprising a second opening formed in the sidewall.49. The port of claim 48, wherein the first opening is diametricallyopposed to the second opening.
 50. The port of claim 48, wherein thefirst opening has a length along a longitudinal axis that isapproximately equal to a length of the second opening.
 51. The port ofclaim 48, wherein the first opening has a length along a longitudinalaxis that is greater than a length of the second opening.
 52. The portof claim 48, wherein the port has a circular cross-section.
 53. The portof claim 41, wherein the port has an oval cross-section.
 54. A systemfor minimally invasive spine surgery comprising: a first dilator havinga first diameter; and a surgical access port comprising a proximal end;a distal end spaced apart a distance from the proximal end; and asidewall defining a lumen extending from the proximal end to the distalend, the lumen having a length sufficient to at least span from a skinincision to proximate a vertebra and a diameter greater than the firstdiameter; and a first opening formed in the sidewall, the first openingdefining a passageway for medical hardware from the lumen to external tothe port.
 55. The system of claim 54, further comprising a plurality ofcanullated dilators of varying lengths and diameters.
 56. The system ofclaim 53, further comprising a first instrument for creating asubcutaneous pathway from the opening in the port.
 57. The system ofclaim 56, wherein the first instrument for creating a subcutaneouspathway comprises a proximal handle, a shaft having a longitudinal axis,the shaft being sized to fit through the lumen of the port, and a distaltip oriented at angle to the shaft.
 58. The system of claim 57, whereinthe distal tip is oriented approximately perpendicular to thelongitudinal axis of the shaft.
 59. The system of claim 58, wherein thedistal tip is sharpened sufficiently to dissect tissue.
 60. The systemof claim 57, further comprising a second instrument, the secondinstrument having comprising: a proximal handle, a shaft having alongitudinal axis, the shaft being sized to fit through a lumen of asecond surgical access port, and a distal tip oriented at angle to theshaft, the distal tip being sized to receive at least a portion of thedistal tip of the first instrument.
 61. The system of claim 54, furthercomprising a spinal rod having a tip configured to dissect tissue. 62.(canceled)
 63. A system for minimally invasive spine surgery comprising:a plurality of cannulated dilators of varying lengths and diameters, theplurality of cannulated dilator including a first dilator having a firstdiameter; a first surgical access port comprising a proximal end; adistal end spaced apart a distance from the proximal end; and a sidewalldefining a lumen extending from the proximal end to the distal end, thelumen having a length sufficient to at least span from a skin incisionto proximate a vertebra and a diameter greater than the first diameter;and a first opening formed in the sidewall, the first opening defining apassageway for medical hardware from the lumen to external to the port;and a second surgical access port comprising a proximal end; a distalend spaced apart a distance from the proximal end; and a sidewalldefining a lumen extending from the proximal end to the distal end, thelumen having a length sufficient to at least span from a skin incisionto proximate a vertebra and a diameter greater than the first diameter;and a second opening formed in the sidewall, the second opening defininga passageway for medical hardware from the lumen to external to theport.
 64. The system of claim 63, further comprising a first instrumentfor creating a subcutaneous pathway from the first opening in the firstport to the second opening in the second port.
 65. The system of claim64, wherein the first instrument for creating a subcutaneous pathwaycomprises a proximal handle, a shaft having a longitudinal axis, theshaft being sized to fit through the lumen of the port, and a distal tiporiented at angle to the shaft.
 66. The system of claim 65, wherein thedistal tip is oriented approximately perpendicular to the longitudinalaxis of the shaft.
 67. The system of claim 66, wherein the distal tip issharpened sufficiently to dissect tissue.
 68. The system of claim 65,further comprising a second instrument, the second instrument havingcomprising: a proximal handle, a shaft having a longitudinal axis, theshaft being sized to fit through a lumen of the second surgical accessport, and a distal tip oriented at angle to the shaft, the distal tipbeing sized to receive at least a portion of the distal tip of the firstinstrument.
 69. The system of claim 63, further comprising a spinal rodhaving a tip configured to dissect tissue.